1. Field of the Invention
The invention pertains to sport lighting luminaires of the asymmetrical type wherein high efficiency of light placement is achieved with a minimum of glare and spillage by the use of an asymmetrical relationship between an arc light source and a parabolic luminaire reflecting surface, light restricting and directing surfaces being defined upon the luminaire reflecting surface, and a visor is used to control light spillage occurring directly from the lamp and from the lower portion of the luminaire without reducing beam utilization.
2. Description of the Related Art
The illumination of sports areas such as football fields, baseball diamonds, soccer fields, and the like, including parking lots, wherein a plurality of powerful luminaires are used to illuminate a particular area is becoming a complex science.
When illuminating athletic fields the area may require a uniform illumination intensity or density throughout the area, or when illuminating a baseball diamond it is desirable that different intensities of illumination be present at predetermined areas, for instance the infield is lighted brighter than the outfield. Powerful luminaires utilizing arc type light sources in conjunction with parabolic reflectors are commonly used for such outdoor lighting, and while such luminaires are capable of producing the desired degree of illumination, considerable problems, and controversy, have resulted due to the inadvertent illumination of adjacent areas. For instance, athletic fields are often located in or near residential areas, and the homeowners object to the high intensities of light being spilled upon their property or home.
The control of light spillage is largely accomplished by the us of glare shields built into the light source lamp, or the luminaire, which are intended to limit the light being cast to those areas intended. It is also known to use visors to control light spillage beyond the remote areas being illuminated, and lens configurations may also be employed. These devices generally also reduce the amount of light delivered to the desired area and thus reduce beam utilization.
As any area directly exposed to the luminaire light source will be illuminated, it is known to locate the light source within the luminaire in such a manner as to reduce lateral light spillage, such as shown in U.S. Pat. Nos. 4,947,303 and 5,016,150. In the art of controlling and eliminating light spillage it is desirable that all areas surrounding the area to be illuminated are not directly exposed to the light source.
The assignee has used special shapes and configurations within the luminaire reflecting surface to direct and confine the light beam as shown in U.S. Pat. No. 4,864,476, and the adapting the concepts shown in this patent permit the light being cast upon areas at different distances from the luminaire to be controlled and regulated, and the present invention employs concepts of this patent, but goes beyond its teaching to provide an even improved ability to control light spillage without reducing beam utilization.